I assume that the honor system was implemented in order to deal with the problem of player hostility, and if such is the case, I believe that the system is short-sighted.
The honor system rewards players for long-term positive behavior. However, I believe that ultimately the honor system will only achieve short-term positive behavior. I predict that Riot will receive a decrease in the quantity of reports shortly after implementing the system followed by an explosion of reports after a certain period of time.
The reason is simple: when players repress the urge to be hostile in order to acquire a reward, and realize, after a significant period of time, that he or she is not not likely to gain a reward (due to the nature of the system), the repressed urge will simply bounce back up again with greater force.